Re:Sun Flyer, an Electric Trainer Aircraft
by ImaMicroService on Wednesday August 23, 2017 @10:16AM
(#15081689)
Oh it's definitely marketing. The author constantly uses possessive semantics when describing the work done. It's a neat idea, and I'd like a cheap electric LSA in the future, but that article was pointed right at VC.
Re:Sun Flyer, an Electric Trainer Aircraft
by blktiger on Wednesday August 23, 2017 @11:51AM
(#15082489)
The weight of the electric motors is definitely a lot less, but what most people don't think about is that the main weight of an electric airplane is in the batteries. The battery pack in a Tesla Model S is ~1300 lbs. The batteries required for an aircraft to have an hour long flight time still add too much weight. Batteries have gotten light enough to make it feasible, but we still need major advances in energy density to make electric airplanes make a lot of sense.
Re:Sun Flyer, an Electric Trainer Aircraft
by sokoloff on Wednesday August 23, 2017 @12:04PM
(#15082618)
Petro-fueled airplanes also have the advantage that they can be flown lighter for short trips, trading off either performance and/or cabin load for fuel load. They also land shorter (by virtue of being lighter) at the end of typical flights.
Battery airplanes that carry the full weight of the batteries all the time have worst-case takeoff, climb, and landing performance on all flights.
It's easy to notice even 100 pounds difference in loading on light airplanes. That's a little under 17 gallons of avgas or about 90 minutes' fuel burn for a typical trainer.
If I want to take 2 extra 175# adults on a local flight, I can just leave off 60 gallons of fuel and have the same performance for a short flight.
A broad torque curve isn't really useful since aircraft engines are already optimized for sustained operation at cruising speed and the range of speeds you can operate at is limited by the propeller and physics. There's no need to have a ton of torque at 1800rpm and at 6000rpm
>At 20 kilograms (45 pounds), the motor can be held in two hands, and it measures only 10 centimeters deep and 30 cm in diameter
And what's the horsepower rating and duty cycle rating on this motor? Power density is not an area where electric motors have a large advantage over ICE unless you're trying to build a cylindrical package. The article talks about doing away with durability requirements that impede a lightweight design.
>with no power-sapping transmission
Most small aircraft are direct drive.
Electric power certainly has advantages but this article may as well be a marketing brochure full of fluff.